Several public opinion polls this week indicate that President Bush's approval rating has dropped to its lowest level since the 2001 terrorist attacks. Political experts say the lower approval ratings are being driven by concern over the domestic economy and worries about the reconstruction of Iraq.

For months, the president's public approval rating has hovered near 60 percent in most polls. But several new polls show his approval rating has now dipped to around 50 percent.

The drop is worrying Republicans and emboldening Democrats, both in Congress and those running for president.

The newest Democratic presidential candidate, retired Army General Wesley Clark, added his voice to the chorus of criticism during a debate this week in New York.

"We elected a president we thought was a compassionate conservative," he said. "Instead, we got neither conservatism nor compassion. We got a man who recklessly cut taxes. We got a man who recklessly took us into war with Iraq."

For the first time, some opinion polls also show the president could be beaten by some of the Democrats looking to challenge him in next year's election.

Democratic political consultant Celinda Lake says, worries about the economy, particularly the loss of jobs, is driving down the president's poll numbers.

"Democrats have picked up on creating jobs a 16-point advantage, and, as we will see, [the issue of] jobs has moved to the Number 1 indicator for the public, in terms of the economy," said Celinda Lake.

Add to the economy the public's concerns over Iraq. Continuing U.S. casualties and the high cost of reconstructing the country have chipped away at confidence in the president's policy on Iraq, even though most polls show a firm majority still believes that toppling Saddam Hussein was the right thing to do.

Even some military families normally supportive of the president are concerned about their sons and daughters serving in Iraq.

Larry Syverson has two sons fighting in Iraq. He has joined a coalition of anti-war groups calling on the president to fire Defense Secretary Donald Rumsfeld.

"Does he consider my son, as well as other sons and daughters in Iraq, disposable? It is playing Russian Roulette [risking the lives of] with other military families, when we hear that another soldier has been killed," he said. "All of us wonder, whose family is it?"

President Bush says he is not paying much attention to his Democratic rivals, and gave an impassioned defense of his Iraq policy in a speech before the United Nations.

"Across Iraq, life is being improved by liberty," said president Bush. "Across the Middle East, people are safer because an unstable aggressor has been removed from power. Across the world, nations are more secure because an ally of terror has fallen."

Administration officials are also defending the president's request to Congress for $87 billion for Iraq's reconstruction.

"Is $87 billion a great deal of money? The answer is, yes," said Defense Secretary Donald Rumsfeld. "Can our country afford it? The answer is also, yes. We believe it is necessary for the security of our country and the stability of the world."

Many Democrats say they are inclined to support the president's request. But they are also urging the administration to build bipartisan support for its approach on Iraq.

California Senator Dianne Feinstein made this appeal to Secretary Rumsfeld at a Senate hearing.

"There is a feeling that you know it all, the administration knows it all, and nobody else knows anything," said senator Feinstein. "And, therefore, we are here just to say, 'yes sir, how high do we jump?' And at some point, we refuse to jump."

Democrats, both those running for president and several in Congress, have intensified their rhetoric on Iraq, accusing the president of misleading the public by overstating the threat posed by Saddam Hussein.

But Mr. Bush defended his actions this week, saying the 2001 terrorist attacks had changed his approach to national security.

"September 11 changed my calculation," he said. "It made it really clear that we have to deal with threats, before they come on our shore."

Republican pollster Ed Goeas says his data indicates that most Americans agree with the president.

"But the American public truly does believe and has moved to a belief on terrorism that you have to get them before they get you," said Ed Goeas. "And they believe that it is better for 200 American heroes to die on the sands of Iraq than 2,000 innocent Americans to die on American soil."

Ed Goeas says that, while his latest poll shows the president's job approval rating down to 54 percent, it also found the president's personal approval ratings at a still high 67 percent. Mr. Goeas says the president's personal likeability will be a major asset in next year's election.